


Boneheaded Caper

by NihilismPastry



Category: Undertale (Video Game)
Genre: Enemies to Lovers, F/M, Fake Dating, Swapfell, Swapfell Papyrus - Freeform, Swapfell Sans, fake dating to real dating, fellswap
Language: English
Status: In-Progress
Published: 2020-03-04
Updated: 2020-03-17
Packaged: 2021-02-28 17:00:22
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 3,693
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23010622
Author URL: https://archiveofourown.org/users/NihilismPastry/pseuds/NihilismPastry
Summary: Basically Swapfell! Sans makes Papyrus pretend to be him for a date with Sans’s human, because obviously, the Captain of the Royal Guard doesn’t want to be outed for being a fucking weeb.In prettier terms:Sans is the Captain of the Royal Guard, a lofty position that doesn't get him respect from those that matter, but does help pay the bills. He's also a massive anime nerd, and runs a certain blog that would get him laughed out of his position. Too bad you send him a message when he needs it the most, and when the two of you agree to meet up, Sans sends Papyrus in his place...
Relationships: Papyrus/Reader, Sans/Reader
Comments: 27
Kudos: 175





	1. Blog 1

**Author's Note:**

  * For [popatochisp](https://archiveofourown.org/users/popatochisp/gifts).



> Gore Level: High

Your jagged nail tapped the mouse for the thirteenth time in the last two seconds. The computer’s fan groaned and sputtered for a few seconds, before the webpage was properly refreshed. A splash of a magical girl wearing frills and lace popped up once again, her face far too smug for your liking. 

“Come on, the new episode came out two hours ago. Where _ is _ he!” 

Your roommate rolled her eyes as she flipped through her D & D manual. “Is it that serious you gotta mess up my computer?” 

“No, but I really wanted to read this before my shift.” You sighed and let your head fall on the desk, a few of the plushies hitting your back as they fell off the shelf. “I like this blog.”

“I know.” 

“It makes me happy.” 

“I’m aware.” There’s the light clap of paper against paper, before a warm hand pressed on your shoulder. “You should eat something before you head out, yeah?”

With popping bones you managed to sit up and push yourself out of the gaming chair, a few stuffed bunnies falling to the floor as you did. You shoved a hand into your slack’s pocket, and pulled out your phone. Your lips curled back and eyebrows furrowed when you noticed the time. You stuffed your phone back in your pocket before half heartedly clicking the mouse a final time…

No update.

You let out a soft sigh that made the hair in your face fan out. You really did enjoy that blog’s deep insight and dry humor. It was less assholish and weebish than the majority of other blogs, and the way the writer compared a character’s experience to his own made the world and its problems feel easier to tackle. Honestly, you had begun to rely on those insightful blog posts on the busiest nights of your shift. And since the writer was punctual, a trait you envied, it was easy to get used to essentially being spoon fed such a nice product. 

Which made you wonder…

Maybe the writer himself was having a bit of a time. Maybe even the latest episode of  _ Princess Samurai  _ really struck a chord with him…

You bent over the chair and clicked on a small envelope icon in a vivid violet. A small text box popped up on the screen, and a submit button hovered below that. You tilted your head as your fingers clacked against the keys, and words began growing like centipedes on the screen. After nearly a paragraph you clicked the submit button, and the text box flew into the envelope. 

“Fancy.” 

“Not as fancy as your GrubHub bill when you gotta order out again.” 

You groaned and sat back up, before rushing out of the small bedroom and down the hall. You forced open the fridge, and scanned the cluttered shelves for boxes that didn’t have stomach churning expiration dates. 

“Come on. Food, food, food…”

**_Honk!_ **

**_Honk!_ **

**_Honk!_ **

You groused and slammed the fridge shut, before grabbing a backpack off the counter and slipping on a pair of low heels. The winter wind fanned out your hair when you ripped open the back door, and you huddled deeper into your wind breaker as you slowly made your way down the apartment steps. 

**_Honk!_ **

**_Honk!_ **

**_Honk!_ **

You stumbled down the long walk way and out to a grossly red van sitting on the curb. You slid open the door and pulled yourself inside, the warm buzz of the heater a welcome feeling even if you were only out for all of a minute. You flopped into the chair and ignored the text books digging into your spine. 

“Really, Tom?” 

The cat Monster just shrugged. “Look, I already got three occurences. If you think Martinez is gonna excuse me because I had to get you, then you’ve got too much faith in someone who doesn’t even know your name.” 

“ _ You _ don’t even know my name.” 

“Be happy I remembered where you live, Princess.” 

You rolled your eyes at the childish nickname, and he pretended he wasn’t grinning around the vape between his fangs. A light jazz played from the radio, and cars sped them by on the snow encrusted road. It was a cozy and warm sort of atmosphere that made your eyes heavy and limbs relax into the small chair you were burrowed in…

That is until you felt a low buzzing in your pocket…

* * *

Sans’s boots crunched in the snow, and his magic steamed the air as he made a beeline through the caution tape and sobbing humans. Police officers, Monsters and humans alike, watched him with narrowed eyes and hands traveling to close to the guns they had holstered to their belts. 

He ignored it all as he walked over to an equally short drake Monster that was leaning against her scythe. She raised an eyebrow, and he waved it off as he dug a hand in his coat and took out his work phone. “You’d think the humans found out they’d be tossed Underground, not stumble upon a murder scene.” 

“I guess then the Underground really did harden us up.” The drake said idly. “Do you remember anything like this?” 

He stared at the rust pentacle drawn on the concrete, the candles still glowing, and the head sitting in the very middle. “Only in movies.”

“You think it’s just some psycho then?” 

He shrugged and idly positioned himself to stand in the parade rest position. “If that’s all that dragged us out here then I’m fucking pissed-”

“Language.”

“You know what I mean.” Violet eye lights glanced around the scene. Blood splattered the alleyway, broken bottles and cans were shoved next to the dumpster, and he could pratically feel the ill intent that was used to murder the human. He took let out a soft sigh, shut his sockets, and let his soul tremble and shake. Like a slick sludge he felt something bubble to the surface. He opened his eye sockets again, and the entire area was a shadow of black filled with white outlines and soft swirls of color. Blues, reds, oranges, and all sorts filled the air in such faint wisps they were almost blended into the black. In the middle of this sea of color was a single glowing series of shards. 

Bingo. 

He strode over to it, just close enough that shakey white words hovered above it. 

**A Dead Soul: It no longer craves a certain sugar.**

**Karmic Retribution: RedacteD**

**Reincarnation: RedacteD**

He let the pulsing in his left eye socket fade, and his parade rest snapped to attention. “Well, we have a clue at least.”

“Do we?” 

“Killed by someone who was, in fact, invoking a ritual.” He turned about-face and looked at the drake. “General Alphys, with your permission I’ll be taking over this case.”

“The Queen’s Spy doing easy police work?” 

“Let’s call it paid time off.” 

Alphys snorted and let her weight fall from the scythe as she twirled it around and attached it to her back. With the second one already strapped there it made the drake look like she had long golden wings curling out of her spine. “Fine, but you get to tell Toriel all about it.” 

“You hate me.”

“Of course I do,” She said cooly. “If I were you, I’d get on that proposal tonight.” 

He watched Alphys make her way out of the alley where a rabble of journalists with their phones and cameras swarmed her like bees. He walked forward, boots crunching through snow and blood, until they were clacking against honey colored wood. He was now in the middle of his living room, the heater blasting down warm air, and the TV still playing the latest episode of  _ Princess Samurai.  _ He scoffed when he could hear the ending theme playing it’s soft piano tones, and sent a haze of violet magic to turn it off. 

His house was plunged in silence, and yet he could still feel his thoughts skittering in his skull like a cockroach. Despite everything that he did, and no matter how hard he worked, he was still disrespected. Unsurprising considering Boss Monsters wouldn’t know respect even if it killed them, but that didn’t stop the bitterness that plagued him when he was dragged out of his house for something so boring and mundane, and then told to work some more just to get the chance to finish the boring and mundane task assigned to him. 

“Uh, bro?” 

“WHAT?” He whipped around, eye sockets narrowed as his brother leaned against the railing of the stairs. “DIDN’T YOU HAVE A NOT DATE WITH UNDYNE?”    
  


“First off: It’s Friendship times. That thing they’ve been teaching in the therapy sessions. Second: Your priceless-never-touch-it-or-i’’ll-die figure is kinda floating.” 

Sans glanced into the living room and found half the contents floating in hazes of violet. He carefully snapped his fingers, and everything began floating back down in place, including the figure of the human wearing nothing but lace and a smile. 

“THANK YOU, PAPYRUS.” 

Papyrus grinned, making his mouth full of gold and white fangs look horrifying. He would never understand how his brother’s jaw didn’t fall off from pain due to the cold. “Kinda what I’m here for.” 

“RIGHT.”

“Oh, by the way.” He tossed a phone that Sans easily caught. “Remember when you said to monitor your website?” 

“YES?” He used magic to warm his hand and the glove so he could use the touch screen. “WHAT ABOUT…”

Sitting in his inbox was a single letter. In the six years he’d been running the blog not a soul had sent him any kind of mail directly. Sure they screamed in his comment boxes, encouraged him in small notes under articles, and generally made a fool of themselves on his social media…

But no one spoke to him directly. 

He hesitantly tapped on the mail icon, and a text box popped open on the screen.

_ Dear Cruel Angel’s Thesis, _

_ For the last year, you always post at the same day, on the same time, and with the same passion. When I logged on and didn’t see your post, I was pretty concerned. Just wanted you to know that it’s okay to take a break and you don’t have to push yourself so hard if you can’t/don’t want to. Your best is always good enough, ya know? _

_ Sincerely,  _

_Wine'sALot_

He scoffed and pocketed his phone. This had to be a joke. Not a single personal email all this time, and now some person just wanted to give him words of encouragement. He snuck a look at his brother, who was now on the couch snacking on what looked like ginger snaps. He wouldn’t put it past the younger Monster to tamper with his things and get his hopes up, especially on a night like this, but…

Well, Sans had been too good at raising Papyrus.

He made a light clacking noise as he ripped his phone out and began tapping out a message. 

_ First of all, your name is a wonderful fucking pun…. _


	2. Blog 2

**Summary for the Chapter:**

> Sans gets a not great idea....
> 
> Gore level: None

_So I actually love high school romantic comedies._

**I’m kinda surprised with that ‘Cruel Angel’s Thesis’ moniker.**

_It’s what one may call a guilty pleasure_ **.**

**You like moe blob anime! Police! Police!**

You stare at your phone for a good five minutes, and when you don’t get a reply, you dropped it in your purse and leaned back in your office chair. The bone grinding sound made your head ache, and only served to remind you of the headset digging into your skull. “It’s so sloooooow.” 

Tom doesn’t look at you as his fingers tap and dance across his keyboard. “You’re complaining? You wanna deal with pissy customers? How about I transfer them all your way?” 

“No, but I don’t wanna be bored either. I knew I shoulda just called out sick today.” 

“So Martinez can fire you?” 

You rolled your eyes at that. “Didn’t you say he didn’t even know my name last week?” 

“That guy is full of surprises.” 

You heard a buzzing from your phone, and you were quick to pluck it up and read the message. For the last week you and your blogging hero had been talking. Everything from anime that he liked, to his favorite articles, and other things you thought to ask. He was to the point with his messages, albeit he texted in sporadic bursts and at odd hours. Granted, you worked the night shift at a call center, so you couldn’t exactly get mad when he texted you at six AM like a fully adjusted adult…

A sharp hiss and a clattering of plastic caught your attention before a large paw settled on your back. You half turned around to look at Tom, who’s eyes were narrowed and ears pinned to the side of his head. “I’m gonna kill her.”

“Who?” 

He showed you his phone, and a grinning human was on the screen. Her thin blonde braids were tossed over her shoulder, a full shot glass between dainty fingers.. Behind her looked to be a stage where a group of people with instruments were likely playing a tune. 

“Mia dyed her hair a color you don’t like?” 

“What? No! I don’t care what she does with her fur- I mean hair. Look!” He jabbed a finger at the screen, and you just nodded along as if you could actually see magic. “That’s a magic band! A real magic band came to South Fall and she went without me!”

“...”

“Fucking…. Dammit.”

Not a word escaped your lips while you let Tom rant his heart out. Their dynamic was a weird one that they both enjoyed. They’d piss each other off, then have angry hate sex, and be fine for awhile. He called it brat taming, and you called it ‘that kinky thing you didn’t know anything about so you shouldn’t judge’. 

A whine from your phone was a quick escape as you scrambled to tap at your keyboard and rip off your headphones. “Finally, time to go home!”

Tom just waved you off. “Yeah, whatever. I still got an hour. Why’d I sign up for overtime?” 

“So you can get a bond mark?” 

He just hissed at you and twisted around in his seat, shoulders hunched and bright orange fur bristling. You ley him be as you ordered a ride home and strode through the long aisles of desks and chairs. A few people were slumped in their chairs, hunched over their keyboards, or doing simple stretches away from their desks. All of them regarded you with thinly veiled jealousy, and you met it all with a grin and a good night. 

You slipped through the dimly lit halls and out the front door. Snow was falling from the sky, and you could feel it sneak past the windbreaker and turtleneck that you wore. Shivering arms wrapped as best they could around your middle in an effort to keep warm. You wished your job at least had security lights, maybe those would help a bit? 

You shuffled closer to the curb and took out your phone. The blue glow lit up your face and made your eyes squint from the sudden bright light. 

Two new texts. 

_I wanted to ask a bit about you. You haven't volunteered any information._

_If that’s not considered forward and too much like a sex starved fiend?_

  
Surprise fills your mind as you slowly absorbed the text. Honestly, you hadn’t expected this to go on for so long. You thought he’d say thanks, and then toss you out on your ass like a poorly made ‘little sister’ anime. 

Was there even anything interesting about you other than your one ‘quirk’. 

You lick your lips and shot out a text. “Way to give someone a quarter life crisis.” 

Your phone buzzed against your fingers, helping the cold along with numbing them. 

_I see that you’re human then. I often forget humans aren’t intune with their souls and can’t just use them to help them find what they naturally like or are inclined to do._

_**So you’re a Monster?** _

_An understatement. The freezing temperatures tend to do more than make us cool._

You rolled your eyes at the poorly made pun and checked on your ride. Looked like it was still ten minutes out…

_I offended you, didn’t I?_

**Yeah, with that stupid pun.**

_Then tell me about you._

**I’m not artistic even though I like anime.**

**I like reading my horoscope every morning.**

God, it was so awkward just listing things out like this. You couldn't think about interesting qualities about yourself, and you certainly couldn't figure out how to do them in a fun or quirky way like they did in movies.

**I like white wines?**

_I could tell._

**I sent one drunk text you ass!**

_I meant your user name, but yes that too._

_You have no alcohol tolerance._

Your eyes narrowed at the challenge. Because, yes, it was clearly a challenge and not an observation. You were horrible at your job, at keeping a clean apartment, and at cooking. However, if there was one thing you could say with pride, it was that your college days had given you a liver of iron and an alcohol tolerance of pure spite!

**I'm gonna prove you wrong!**

**Meet me at Winner’s Circle tomorrow night.**

Your phone buzzes against your fingers, and you click out of the texting app and to your ride’s app. Glowing in a soft yellow was your ride alerting you that they were at the back of the building. You groaned and began the long and hard trek along the uneven sidewalk. You could see your texting app flashing, but you ignored it when you finally saw the bright red van sitting next to the back door of the call center. 

“Wine’salot?” The old woman sounded credulous with your old name, but you just nodded along and got into the van. “You work hellish hours, girl. I couldn’t do that.” 

“Eh, it’s easy.” You leaned back in your chair. “O the directions are going to give you the wrong way, so I’ll lead you on.” 

Your phone buzzed once more, this time back to back several times. You ignored it in favor of finally getting home after a ten hour shift…

* * *

Sans stared at his phone with eye lights that rumbled and shook like a flickering TV screen, and glowed a wilted shade of violet. He slammed his phone on his desk and pushed his chair back, before making his way out of the office and into the living room. Papyrus was perched on the couch with a motor on the table and tools precariously spilling out of a tool box. 

“Papyrus, you still go on escapades with humans right?”

The skeleton didn’t look up from the motor as he ran a brush along with the nooks and crannies. “Weird, you didn’t call it a fetish. You’re not adding magic to your words either. I’ll take a dinner at that fancy place on West End, thank you.” 

“You don’t even know what I want.” 

“Something big if you don’t just outright say it.” He looked up for the first time, his own violet eye light glowing brightly under his brother’s scrutiny. “I got ya number, bro.” 

“You hacked my phone?” 

“Nah, but I’ve known you for almost a century, so….” He shrugged. “But yeah, I still have friends with benefits. Why? I thought you didn’t like having sex without commitment?” 

Sans scoffed and waved his hand. “NOT WHAT I MEANT. A HUMAN HAS ASKED…. IF I WOULD JOIN HER FOR A DRINK.” 

“So a date?”

“NOT A DATE.” His browbones furrowed. “ACTUALLY, SHE CAN’T EVEN MEET ME.”

“I’m confused?” 

Sans stepped over the tool box, and pushed aside the strewn fabric of the heavy coat Papyrus had left on the chair. It fell with a clatter and ringing thanks to all the chains, buttons, and zippers. “SHE KNOWS ABOUT MY… FASCINATION WITH JAPANESE MEDIA. CAN YOU IMAGINE HOW LITTLE I WILL BE RESPECTED IF THAT GOT OUT?” 

“Dunno, people are scared of Undyne just fine.” 

“SHE’S ONE OF THREE MONSTERS THAT WILLINGLY USES HER HEALING MAGIC.” 

“Touche.” Papyrus leaned back in the chair, his head tilted up to stare up at the ceiling. “Is she weak?” 

“I HAVEN’T USED _IT_ ON HER. I DOUBT SHE CARES ENOUGH TO LEAVE SOUL RESIDUE THROUGH HER WORDS.” 

“Well, let’s go and figure it all like this.” Papyrus held out one gloved finger. “You know that she’s human, but you don’t know how strong she is as a human.” He held out another finger. “She interests you enough to move your ass, but it’s already happened so it won’t catch you off guard too much next time.”

“IT’S STILL PRECARIOUS.” 

Papyrus shrugged and pushed himself up, hunching over the motor again like some kind of gargoyle. “You asked.”

“I KNOW…. Thank you.” 

Papyrus shrugged again, a hand reaching up to fiddle with the strings of his eye patch, words slipping between jagged teeth as he dove in thought. Sans sighed and pushed himself up, hands coming behind him to sit at the bottom of his spine in a comfortable position. This was so annoying, he liked being in the shadows and waiting for things to blossom and develop until the time was right. Actively working things was more of his bother’s passion, and he was certainly not his….

He snapped his head to the side, the edges of his grin picking up and spreading. Papyrus shuddered and glanced back at him with furrowed eyebrows and a narrowed eye socket. “I could hear you smile, bro.” 

“SANS.”

“What?” 

“Starting tomorrow you’re going to be Sans.” 

Papyrus made a hissing noise like a pissed off cat. “No, I’m not going on a date for you. Do you know how-”

“IT IS THE GREATEST ANIME CLICHE,” He said. “IT’S PERFECT. I’LL WRITE UP A CONTRACT AND YOU CAN SIGN IT IN THE MORNING.”

“Heck no! You always have a better lawyer.” 

“IT’S ABOUT WHO YOU KNOW, BROTHER DEAR.” He strode back to his office. “NOW WHERE IS NAPSTATON’S NUMBER…”

**Notes for the Chapter:**

> Yup, this show is getting on the road! Know what isn't on the road? My Twitter! https://twitter.com/NilPastry

**Author's Note:**

> This is a self indulgent fic with so many of my favorite trope guys. That's it. No what isn't trope filled? My Twitter!


End file.
